This application relates to the art of condition responsive alarms and, more particularly, to alarms that are activated in response to an undesirably high water level. The invention is particularly applicable for use with electric sump pumps and will be described with specific reference thereto. However, it will be appreciated that the invention has broader aspects, and that certain features of the invention may be used for other purposes and in other environments.
A submersible sump pump typically is operated by an automatic float switch that turns the pump on when the water level in a sump or pit rises above a predetermined level and shuts the pump off when the water level falls as a result of pump operation. These switches are well-known in the industry for use in controlling the level of water in the sump and commonly are referred to as float, tether, or electronic sensor type switches.
When a switch or pump fails to operate due to defect, malfunction, power outage or blockage in the system, the water level rises in the sump and ultimately may lead to a flood in that location. The water level also may rise due to an excessive inflow of water that exceeds the pump flow capacity. A known commercially available water sensor has metal or metalized contacts and activates an audible alarm when bridged with water. These water sensor alarms may sit on the floor in proximity to the sump, or may have an extension of wire that permits the contacts to hang down into the sump pit from above.
It is extremely difficult to precisely locate existing devices for providing the earliest possible warning to a homeowner. The surfaces of contact sensors that are exposed to basement moisture and ground water develop mineral deposits that act as an electrical insulator and prevent the alarm from being actuated when the water level rises too high.
Independent contact sensors are difficult or impossible to locate precisely at a given height when used with a submersible sump pump. Typically, they are mounted outside of the sump on the basement floor and provide a late warning only after the water has already breached the sump pit. A contact sensor mounted to a pump inside the sump pit at a height low enough to give an early warning would be highly susceptible to false alarms. This is because the entry of water into a sump most commonly is from drain tiles located at or above the top of the pump and this causes splashing that may trigger a contact sensor.
There is no easy or reliable way for the end user to accurately install a sensor for a given pump at the correct height to be low enough for early warning while avoiding false alarms.
In accordance with the present application, an alarm float switch assembly is incorporated into the physical structure of the pump itself. This makes it possible to customize the alarm system to each type of pump for providing early warning of an impending problem while minimizing any tendency to trigger false alarms.
In a preferred arrangement, the alarm float switch assembly includes a sealed switch that may be an encapsulated reed switch. In this preferred arrangement, a float that surrounds the reed switch and carries a magnet is lifted by an undesirably high water level to operate the reed switch and activate an alarm. The alarm switch may be either normally open or normally closed, and is moved to its opposite state for triggering the audible alarm.
The alarm float switch assembly may be arranged to activate the alarm when the water level rises between xc2xd to 2 inches above the normal maximum operating water level. Location of the float alarm switch assembly for triggering the alarm at a water level 1 inch above the normal maximum operating level is an optimum location to provide the earliest warning practical while avoiding false alarms due to water turbulence.
The audible alarm is located in an enclosure that includes the power plug. The alarm is battery operated and a battery compartment is located in the rear of the enclosure. The act of placing the power plug in an electrical socket automatically positions the audible alarm in a highly desirable location for being heard because the electrical receptacle normally is at least several feet above floor level. Replacement of the battery requires separation of the power plug from the electrical socket.
In accordance with one arrangement, the alarm switch is mounted on a switch support that is secured to the top end of the pump housing and projects outwardly therefrom. A magnetically operated reed alarm switch depends from the switch support and has a float carried thereby. A combined cover and strain relief member is positioned over the switch support to protect the switch alarm wire that extends from the reed switch to the alarm module in the remote enclosure.
In a preferred arrangement, the power cord and alarm switch wire extend from the remote enclosure to the pump housing through a flexible corrugated tube having an end portion attached to the pump housing at the switch support by a strain relief connection. An upright support sleeve on the switch support is received in an open end portion of the corrugated tube and has a plurality of outwardly extending circumferential ribs received in internal circumferential grooves within the tube. The combined cover and strain relief member has opposed parts with an opening therein that fits around the upright support sleeve and the end portion of the corrugated tube. A plurality of inwardly extending circumferential ribs on the cover member are received in external circumferential grooves on the corrugated tube. Reception of the ribs within the internal and external grooves on the tube prevents longitudinal separation of the corrugated tube from the pump housing.
In a preferred arrangement, the end portion of the corrugated tube is not tightly clamped or compressed between the opposed parts of the cover member and the upright support sleeve, and the fit is such that the corrugated tube can rotate relative to the upright sleeve and the cover member while being incapable of longitudinal separation therefrom.
The advantageous type of strain relief provided by the corrugated tube attachment may have applications in many different devices other than sump pumps.
It is a principal object of the present invention to provide an improved alarm switch arrangement for a sump pump.
It is also an object of the invention to provide an improved connecting arrangement for connecting an end portion of a corrugated tube to a housing without crushing or compressing the corrugated tube.
It is a further object of the invention to provide a sump pump with a float alarm switch assembly having a sealed switch that is magnetically operated by a magnet carried by a float that slides along the sealed switch.
It is a further object of the invention to provide an alarm arrangement for a sump pump wherein an audible alarm is located in a remote enclosure along with the pump power plug.